Researchers from the University of Glasgow have developed a new type of heat pump, a flexible heat pump technology, which could help households save on their energy bills and contribute towards net-zero emissions goals.
When heat pumps are powered by renewable sources they are significantly more environmentally friendly than conventional gas boilers. The UK government has set a target for 600 000 heat pump installations per year by 2028 in order to reduce the country’s carbon footprint.
However, the heating capacity and energy efficiency of the current generation of heat pumps can be adversely impacted by cold weather, particularly for air source heat pumps. High capital and operational costs and relatively low heat supply temperature have limited the growth of their take-up in the UK. Innovations are therefore needed to improve the cost-effectiveness of heat pumps to compete with fossil-fuel-based heating technologies.
In a new paper published in the journal Communications Engineering, the researchers outline how their flexible heat pump technology provides a simple and low-cost solution to the problems of current heat pumps by integrating heat storage – a small water tank and a coil of copper tube.
The water tank recovers some excess thermal energy produced during the pump’s operation, and stores it as an additional heat source for the heat pump’s operation later. The recovered heat has a much higher temperature than the outdoor air that provides the heat source, and it can be reused as a temporary heat source, substantially reducing power consumption. For air source heat pump applications, the recovered heat stored in the water also allows the flexible heat pump to run continuously during defrosting. That makes it more efficient and effective than the current generation of heat pumps, which interrupt the heat supply during defrosting while still consuming electricity.
The researchers have demonstrated the advantages of their new heat pump by building a working prototype using off-the-shelf components. Thorough testing against current-generation heat pump designs has shown their design to be around 3.7% more efficient than current design with a relatively low heat supply temperature of 35 °C.
When the supply temperature increases, so does the amount of energy recovered, improving the system’s efficiency and saving more power. The team’s analysis predicts that, after optimisation, it could be up to 10% more efficient than current products when the heat supply temperature increases to 65 °C.
The research team has protected its invention with a PCT patent and is actively looking for ways to make the flexible heat pump technology commercially available in the near future.
The team’s paper, titled ‘A flexible heat pump for heat recovery’, is published in Communications Engineering, a Nature portfolio journal. The research was supported by funding from the Engineering and Physical Sciences Research Council. The team is currently seeking collaborators to take forward the development of this flexible heat pump technology.